There's definitely the idea of a game here for sure. I think committing to the shapes instead of enemies is fascinating if you're going for a more retro-inspired look. Matching up the music with that in mind would have done wonders. That said, it was kind of confusing to know what was what. Apparently the white circles are good, but they behave like something bad (since other white shapes are enemies), so it complicates gameplay. The hitbox was also extremely large for a Touhou game; I found myself dead very often from getting pixel-clipped-- which is especially a pain when you only have three lives and the bullets are the size of you.
All said, however, for a three-day project, this is pretty interesting. I would have been very interested to see what it looked like with about a week or so instead.